How do I troubleshoot an empty ZCenter monitoring report or blank page?

Issue/Introduction

This article describes how to troubleshoot a blank ZCenter monitoring report page, a Grafana panel without a graph, or a resource monitoring API that returns no data. The blank state can originate in Grafana, Prometheus, a monitoring synchronization task, target resource labels, or the cloud platform metrics API. Do not assume that Grafana is the cause.

Symptoms

• The monitoring report page is blank, or a panel displays No data.
• The monitoring page opens, but the cloud environment or resource drop-down list is empty.
• 1 resource has no data while other resources work, or no resource has data.
• A monitoring API returns an empty array, and a Prometheus query matches no time series.
• The VM service log might contain MetricDataApiImpl has no executable configuration info, the mo didn't get any metric data!, sync cloud metric error!, or sync metric data error!.

Environment

• Product: ZCenter
• Version: 5.1.0
• Component: VM service, Prometheus, Grafana, and monitoring synchronization tasks
• Resource types: VMs, physical hosts, bare metal instances, or storage resources

Possible causes